One television show defined the police series genre in the Nineties: NYPD Blue, which first aired on September 21, 1993, and ran until March 2005.

Most television that is two decades old looks rather worn but NYPD Blue was such a strong programme that it has stood the test of time; it's still clear why it won nine Emmys, four Golden Globes and three Screen Actors Guild Awards. It ran for 12 seasons, and all are now available on DVD after a long-running dispute over rights was finally settled this year.

The series was created by David Milch and Steven Bochco and although the show was initially a vehicle for David Caruso (as the main character, Detective John Kelly), he lasted only one full season after falling out with his bosses. His replacement, Jimmy Smits (as Bobby Simone) was infinitely preferable.

Yet standing as the colossus throughout was Dennis Franz, as Andy Sipowicz (below), who dominated a shifting cast and was the only actor to appear in all 261 episodes. Franz, who had previously starred as both Lt Norman Buntz and Detective Sal Benedetto on Bochco's Eighties cop show Hill Street Blues, plays one of the best television detectives ever.

Dennis Franz, who played NYPD Blue's Andy Sipowicz (Reuters)

Franz, who had served 11 months with the 82nd Airborne Division in Vietnam, came late to acting and was utterly believable as the recovering alcoholic cop. Although Sipowicz could be a hot-tempered bully and a bigot, he was also a dedicated and shrewd detective and a man who finds a path of redemption by overcoming his prejudices and quitting drinking. The regulars around Franz were good, too. Gordon Clapp was terrific as Medavoy – a walking bundle of neuroses, with an unerring ability to put his foot in his mouth – and there were strong women detectives, too, especially Detective Diane Russell (Kim Delaney).

Plot lines tended to add up (sometimes ending a little too cosily) and the dialogue, occasionally with profanities, crackled along. NYPD Blue co-creator Milch developed an idiosyncratic dialogue style that used real cop lingo. Even in the UK, you knew it was not good to be called a "hump".

NYPD Blue was set (of course) in New York City with the detectives working in the fictional 15th precinct. The bulk of the filming was actually done in Los Angeles and a lot of the show was shot with handheld cameras in an attempt to simulate a detective's point of view and to give episodes a cinéma-vérité feel. The show was also notable for many fine guest actors, from David Schwimmer (who is in the first four episodes) to Sam Rockwell, Lucy Liu to Debra Messing. One of the charms of the whole box set experience is spotting the guest stars, and you may shout out in victory, as I did, after spotting Breaking Bad's Giancarlo Esposito (season 3, episode 17).

Kim Delaney as Detective Diane Russell (Reuters)

Looked at from a 2013 perspective, NYPD Blue lacks the grit and nastiness of The Shield (Bochco's cops were mostly very moral) and it seems odd now to consider how much of a controversy there was about the occasional nudity. Bare bums and nipples prompted the American Family Association to call it a "soft-core porn" series and take out full page adverts in major newspapers, asking viewers to boycott the show.

There remain so many interesting things about the show, all the way down to the violin heard at the end of every episode, which was Bochco's father Rudolph playing an excerpt from Vivaldi's The Four Seasons. Franz seems to have pretty much retired, although the 68-year-old will serve as grand marshal of the holiday parade in Santa Barbara, California, in December.

Bochco once said that successful TV "always comes down to characters" and in NYPD Blue they were made to last.